The Traumatic Coma Data Bank is a prospective observational study which collected data on severely head injured patients at four clinical centers. The four collaborating centers were responsible for the collection of acute care and longitudinal follow-up information using common definitions and procedures, under contracts N01-NS-3-2339-42. The research objectives for the project were formulated by a Steering Committee composed of the principal investigators from the clinical centers, other outside experts, and BFSB staff, with the concurrence of the BFSB Advisory Committee. The research objectives were the basis for determining the specific data to be collected, the format of the data collection forms and the data collection procedures. The general objective for the project was to provide a large and comprehensive body of data for clinical research on the factors influencing survival, morbidity and quality of life following a severe head injury. The BFSB was the statistical coordinating center for the project, providing an on-site front-end data entry system with interactive feedback for data editing; and the data base management system for transmission, storage and retrieval of data, for monitoring of data acquisition and its quality; and for statistical collaboration with the clinical investigators and statistical analysis oversight for the primary research questions of the data banks. Accrual of 1030 patients was completed in September 1987, and the data have been entered and edited. The focus of the Branch during the data collection period has been on the monitoring of the project with regard to completeness and quality of data collection, and the emphasis will now shift to analysis of these data.